Gripper mechanism



Dec. 2l, 1954 A. R. HUBBARD GRIPPER MEcHANrsM -Fled Oct. 1'?, 1952 United States Patent() GRIPPER MECHANISM Arthur R. Hubbard, Beverly, Mass., assigner to United Shoe Machinery Corporation, Flemington, N. J., a corporation of New Jersey Application October 17, 1952, Serial No. 315,258 21 Claims. (Cl. )l2-14.5)

trated as applied closed in U. S. Letters Patent No. 2,663,035 granted on December 22, 1953 in the name of Lloyd G. Miller. It will be understood, however, that the novel gripper mechanism of this invention is not limited to use in a machine of this type or to embodiment in the exact mechanical construction herein disclosed.

As is pointed out in the mentioned application, the lasting machine therein disclosed and described is especially adapted for high-speed operation. The gripper of this prior machine includes a relatively fixed jaw and a movable jaw which, during each operating cycle, is

erating link which is yieldingly actuated by mechanism including an adjustable spring and a power-operated reciprocating member. After the gripper jaws have been closed they are moved in a direction to exert a yielding tensioning pull on the stock as a result of continued movement of the operating link and against the resistance of a friction device which is arranged to resist movement of the gripper jaws in either direction. Finally, the jaws are opened to release the stock and the opened jaws are returned to their original positions, against the resistance of the friction device, as a result of a reverse movement of the operating link which is effected positively by operating connections associated with the link, gripper, and the power-operated reciprocating member, thus completing an operating cycle. While this type of gripper mechanism operates in a generally satisfactory manner, it has been found that, when the lasting machine is operating on certain types of stock and at the relatively high speed for which it is intended, there may be some tendency for the movable gripper jaw, as it is brought into engagement with stock inserted between the two jaws, to bounce or rebound in a direction away from the iixed jaw,` thereby momentarily releasing the grip of the jaws on the stock. The action, if present at all, occurs just as the gripper jaws commence to move in a direction to apply their tensioning pull so that, to a greater or lesser extent, the effectiveness of the moving jaws to tension the stock is reduced.

lt is, therefore, a principal object of this invention to provide a novel and improved gripper mechanism which avoids the mentioned dithculty and which is effective and dependable in. action when operating at high speeds and on all types of materials. To this end, the herein illustrated gripper mechanism, which is in many respects similar to that of the prior machine and has a fixed jaw and a movable jaw which is yieldingly moved toward the fixed jaw by an operating link, is provided' with additional means for yieldingly urging the movable jaw toward the iixed jaw and the' yieldable force applied by this additional' means is suicient to prevent the movable jaw from bouncing, or rebounding away from the fixed jaw as the movable jaw is brought into engagement with the stock inserted between the jaws. Thus, because of the force applied by this additionai means, the movable jaw cannot bounce away from the stock and a continuous andy uninterrupted grip on the stock is assured so that the entire movement of the closed jaws is eiiective to apply a tensioning pull on 2,697,237 Patented Dec. 21, 1954 ICC the stock. More particularly, the additional means for moving the movable jaw toward the fixed jaw comprises an adjustable spring conveniently located within a hollow shaft provided for supporting the gripper jaws. As in the gripper mechanism of the prior machine, the operating link is connected directly to the movable jaw which is pivotally mounted on this shaft and another close the jaws and to cause them to tension the stock. Also, a friction device is provided for resisting movement of this shaft in either direction and positive drive connections are interposed between the link and the reciprocating member for positively moving the link in a direction to open the jaws and between the reciprocating member and the shaft for returning the opened jaws to their original position.

In addition to preventing the movable jaw from bouncing or rebounding away from the stock, as above explained, the provision of the spring means for urging the movable jaw toward the iixed jaw has another practical advantage. It will be appreciated that, in the gripper mechanism of the prior machine, the firmness of the grip of the jaws on the stock is dependent upon the force of the pull exerted on the stock as the closed jaws are moved upwardly against the resistance of the friction device by the operating link. Hence, when operating on relatively light material which need be subjected only to a tensioning pull of low intensity, it may be diiicult to obtain a iirm enough grip on the stock to prevent slippage. However, with the additional spring means for urging the movable jaw toward the fixed jaw, the desired gripping force can readily be obtained regardless of how light a pull is being applied through the action of the gripper-operating spring. Accordingly, the adaptability of the lasting machine is extended to a wider range of materials and operating conditions.

The above and other objects and features of the invention will become apparent from the following detailed description of a preferred embodiment thereof, illustrated in the accompanying drawings, and will be pointed out in the claims.

In the drawings,

Fig. l is a view in side elevation of a portion of a lasting machine embodying the novel gripper mechanism of this invention;

Fig. 2 is a view in front elevation of a portion of the gripper-operating mechanism shown in Fig. l with certain parts in vertical section substantially on line ll-II of Fig. l and looking in the direction of the arrow;

Fig. 3 is a view in vertical section of another portion of the gripper-operating` mechanism, shown at an enlarged scale; and

Fig. 4 is a view of a portion of the mechanism shown in Fig. l drawn at an enlarged scale. i

Referring to the drawings, and particularly to Fig. l thereof which corresponds generally to Fig. 5 of the drawings of the above-mentioned Miller patent, the improved gripper construction is therein shown as supported on and operated by mechanism contained within a head casting having upper and lower portions 10 and 12, parts only of which are illustrated. The gripper hasa iixed, or stationary, jaw 14 which is secured to a bracket member 15, and` a movable jaw 16 which is secured to one end of a lever 18 by means of a screw 20. This lever is pivotally mounted on` the bracket member by means of a pivot pin 22 and connected to its opposite end by means of a ball joint, indicated generally by the reference character 24, is an operating link 26. The bracket member 15 is secured to the lower end of a shaft 2S which is journaled in bearing bushings 30, 32 associated withA the lower portion 12 of the head casting. This shaft is` ofhollow construction, being traversed by a bore 34 which, near the lower end of the shaft, is reduced in diameter to provide a shoulder 36. Connected at its lower end to one arm of the lever 18, by means of a pin 38, is a rod 40 which extends upwardly within the bore 34 toa point near `the upper end of the shaft 28'. The upper end of this rod is threaded to receive a sleeve 42 which is provided with a head 44, Fig. 4, and interposed between this head and the-shoulder 36 of the bore 34 is a relatively long compression spring 46, the purpose of which will be explained below. The lengthwise position of the sleeve 42 on the rod 40, and hence the length of the spring 46, may be varied by rotating the sleeve on the threaded portion of the rod and the sleeve may thereafter be locked in position by means of a clamp nut 48, access to which is provided by the removal of a threaded plug 50 from the upper end of the bore 34 in the shaft 28.

Secured to the mid-portion of the shaft 28 is a sleeve 60 which is provided with spaced flanges 62, 62 between which two trunnion blocks (not shown) are received. These trunnion blocks are mounted on the bifurcated arm of a lever 64 which is secured to a friction shaft 66 (corresponding to the shaft 68 of the machine disclosed in the Miller patent). Associated with this shaft and the portion 12 of the head casting is a friction device similar to that disclosed in the mentioned Miller patent which resists rotation of the shaft 66 and axial sliding movement of the shaft 28 in either direction. Briefly described, this friction device includes a plurality of friction plates 76, which are splined onto an enlarged hub portion 72 of the shaft 66, and a plurality of friction plates '74, which are splined onto a hub portion 76 formed on a disk 78 which is pinned to the head casting portion 12, Fig. 3. Connected to the shaft 66 is a rod titl which passes through a pressure cup 82, and bearing against this cup, and adjusting nuts 84 threaded onto this rod, is a compression spring 86 which forces the friction plates 70, 74 yieldingly together into frictional engagement.

The operating link 26 is connected at its upper end, by means of a ball joint indicated generally by the reference character 90, to an arm 92 which is pivotally mounted on a shaft 94, one end of which is journaled in the sides of the casting portion 10, Fig. 2. Keyed to a portion of this shaft of reduced diameter is the hub of an arm 96 which is offset so as to overlie the arm 92, see Fig. l. Keyed to the other end of the shaft 94 is a worm quadrant 98 having a hub portion 100 which is journaled in a bearing carried by an outwardly extending portion 102 of the casting 1i) and journaled on this hub portion is a housing 104 in which there is rotatably mounted a worm 106 which is in mesh with the worm quadrant 98. Connected to this worm, by means of a short shaft (not shown) is a hand wheel 107, Fig. l, by means of which the worm may be rotated to vary the angular relationship of the quadrant 98 and housing 104. Surrounding the shaft 94, the hub portion of the arm 96 and a sleeve 108 which is interposed between this hub portion and the worm quadrant 98, is a torsion spring 111 anchored at its opposite ends on pins 110, 112 carried, respectively, by the arm 92 and the housing 104. As will be apparent, when the shaft 94 is oscillated in a clockwise direction, Fig. l, the arm 92 will be swung yieldingly in the same direction, through the action of the spring 111, thereby elevating the link 26. On the other hand, when this shaft is oscillated in the opposite direction, i. e., counterclockwise as viewed in Fig. l, the arm 92 will be positively swung in the same direction by the offset arm 96, thereby moving the link 26 downwardly.

For thus oscillating the shaft 94 and thereby reciprocating the link 26 in a vertical direction, there is keyed to this shaft the hub portion of a bifurcated arm 120, and connected to this arm is one end of a connecting rod 122 which corresponds to the link 114 of the machine disclosed in the mentioned Miller patent. The other end of this connecting rod is connected to a block 124 which is slidably mounted in an arcuate guideway 126 formed in an arm 128 which is journaled on a stud 130, carried by the head casting portion 12. Connected to an ear 132, formed integrally with the arm 128, is a link 134 which is mounted on an eccentric 136 carried by a main power shaft 138. When the block 124 is displaced downwardly from the on-center position in which it is shown in Fig. lby mechanism similar to that illustrated in the Miller patent and including a link 140, the connecting rod 122 will be reciprocated to oscillate the shaft 94 in response to the oscillation of the arm 128 by the eccentric 136.` As in the machine disclosed in the Miller patent, the shaft 28 and gripper jaws 14, 16 are oscillated about the axis of the shaft 28 during the operation of the gripper. Accordingly, an adjustable link 150 is connected .at one end to a pin 152, carried by the sleeve 68, and at its other end to one arm of a bell-crank lever 154. Adjustably connected to the other arm of this bell-crank lever is a link 156 which issmouuted on a second eccentric 158, carried by the shaft 1 8.

Also connected to the bifurcated arm 120, below the connecting rod 122, is one end of a link 160 which extends downwardly through holes formed, respectively, in a U- shaped thrust member 162 and in an enlarged central portion of a trunnion pin 164 which is journaled in another bifurcated arm of the lever 64. Threaded onto the lower end of this link are an adjusting nut 166 and a locknut 168 and interposed between the adjusting nut and the thrust member 162 is a resilient rubber bushing 170.

The operation of the improved gripper which has been described above is, in general, similar to that of the gripper disclosed in the Miller machine. Thus, during each of its cycles of operation, the following actions occur. First, as the shaft 94 is oscillated in a clockwise direction, Fig. l, the link 26 is moved upwardly and the lever 18 is swung in a direction to move the jaw 16 toward the jaw 14, thereby closing the jaws on stock interposed therebetween, upward movement of the shaft 28 and of the two gripper jaws at this time being prevented by the action of the lever 64 and the friction device which is shown in Fig. 3. After the jaws 14, 16 have thus been closed to grip the stock, the continued upward movement of the link 26 overcomes the resistance of the friction device and elevates the gripper jaws and shaft 28 to tension the stock yieldingly under the action of the torsion spring 111 the tension of which may be varied by means of handwheel 107. During this oscillation of the shaft 94 in a clockwise direction, the link 160 slides freely downwardly through the holes in the member 162 and in the trunnion pin 164 so that the resilient rubber bushing 170 is moved away from the member 162. Now, as the shaft 94 is oscillated in a counterclockwise direction, Fig. 1, downward movement of the shaft 28 and the gripper jaws 14, 16 is at first prevented by the action of the friction device so that the jaw 16 is swung away from the jaw 14 by the downwardly moving link 26. During an initial portion of the counterclockwise oscillation of the shaft 94, the arm 92 is held up by the action of the torsion spring 111 until the offset arm 96 cornes into contact with the arm 92 whereupon the arm 92 is positively swung in a counterclockwise direction and the link 26 is positively moved downwardly as the shaft 94 completes its counterclockwise oscillating movement. Just at the time when the jaws 14 and 16 have been fully opened, the upwardly moving link 160 draws the resilient rubber bushing 170 into engagement with the thrust member 162 and thereafter, the shaft 28 and the two gripper jaws are moved downwardly, against the resistance of the friction device, simultaneously with and at substantially the same rate as the downwardly moving link 26, thus completing an operating cycle of the grippers.

As has been indicated above, the lasting machine disclosed in the Miller patent is especially adapted for highspeed operation. Accordingly, during each operating cycle of the gripper, the movable jaw is moved very rapidly toward closed position and into engagement with the stock interposed between the jaws. Because of the rapidity of this closing movement there may be a tendency for the movable jaw to bounce, or rebound away from the fixed jaw, thereby momentarily releasing the grip of the jaws on the stock, just as these jaws commence to move in a heightwise direction to apply their pull. When this occurs, the stock slips through the upwardly moving jaws and the effectiveness of the gripper to tension the stock is correspondingly reduced. By providing, in the im proved gripper mechanism which has just been described, an additional means, and more particularly an adjustable spring contained within the hollow gripper shaft, for yieldingly urging the movable jaw toward the fixed jaw, this tendency is entirely eliminated so that a continuous and uninterrupted grip of the jaws on the stock is assured and these jaws are rendered effective to tension the stock throughout the entire extent of the heightwise movement of the gripper. Also, by providing the additional spring 46 for yieldingly urging the movable jaw toward the fixed jaw, it is possible to assure an adequate gripping force regardless of how light a pull is being applied to the stock through the action of the gripper-operating spring 111.

Thus, the firmness of the initial grip of the jaws is independent of the intensity of the pull, yet as the pull isv applied to the stock the gripping force is increased in direct proportion to the tension applied by the gripper. As will be apparent, the action of the additional spring 46 may be varied by adjusting the position of the sleeve 42 on the upper end ofthe rod 40. Alsof, if itl is desired to accommodate various working conditions, springs of different strength may readily be substituted in place of the spring 46 then in use. In addition, by locating the additional-spring 46 and its operating rod 40 within the hollow gripper-supporting shaft 28, the dynamic balance of the gripper, during its oscillating movements aboutthe vertical axis of this shaft, is not disturbed.

Having described my invention, and desire to secure by Letters States is:

l. In a lasting machine, an intermittently operating gripper for seizing and tensioning the stock tobe lasted, successively, in different locations along the marginal edge of the bottom of a shoe, said gripper comprising a fixed jaw and a movable jaw, power-operated means for yield-V whatA I claim as new' Patent of the United able jaw toward the fixed jaw, the power-operatedv means fory positively moving the movable jaw away from the fixed jaw, against the resistance of said additional means, to open the jaws and' release the stock and for thereafter positively returning the opened jaws to their original positions;

2. In a lasting machine, an intermittently operating gripper for seizing and tensioning the stock to be lasted, successively, in different locations along the marginal edge of the bottom of a shoe, said gripper comprising a fixed jaw and a movable jaw, power-operated means for yieldingly effecting movement of the movable jaw toward the fixed jaw to cause the jaws to close and seize stock inserted therebetween and for thereafter moving saidy closed' jaws in a direction to exert a yielding tensioningpull on` the stock, spring means for yieldingly urging the'movable jaw toward the fixed jaw, and means associated' with the power-operated means for positively movingthefm'ovable jaw away from the fixed jaw, against the resistance of said spring means, to open the jaws andi release the stock and' for thereafter positively returning the opened jaws totheir original positions.

3. In a lasting machine, an intermittently operating gripper for seizing and tensioning the stock; to be lasted, successively, in different locationsalong. the marginal edge of the bottom of a shoe, said gripper comprisinga fixed jaw and a movable jaw, power-operated means for yieldingly effecting movement of the movable jaw toward the fixed iaw to cause the jaws to close and seize stock inserted therebetween and for thereafter moving said' closed jaws. in a direction to exert a yielding tensioning pull on the stock, adjustable spring means for yieldingly urging the movable jaw toward the fixed jaw, and means associated with the power-operated means for positively movinggthe movable jaw away from the fixed jaw, against the resistance of said spring means, to open the jaws and release4 the stock and for thereafter positively returningthe opened' jaws to their original positions.

4. In a lasting machine, an intermittently operating` gripper for seizing and tensioning the stockv to be' lasted', successively, in different locations along the marginal edge of the bottom of a shoe, said gripper comprising a fixed' jaw and a movable jaw, power-operated means for yieldingly effecting movement of the movable jaw toward the fixed jaw to cause the jaws to close and seize stock nserted therebetween a-nd`for thereafter moving ,saidclosedl jaws in a direction to exert a yielding tensioning pull on the stock, additional means movable with the gripper for yieldingly urging the movable jaw towardv the fixed jaw, and means associated with the power-operated'. means. for positively moving the movable jaw awayvfrom the fixed jaw, against the resistance of said additional" means, to open the jaws and release the stock andv for thereafter po.- sitively returning the open jaws to their originalpositions.

5. In a lasting machine, an intermittently operating gripper for seizing and tensioning the stock to be lasted,V successively, in different locations along the marginal edge of the bottom of a shoe, said gripper comprising a fixed' jaw and a movable jaw, power-operated means for yieldingly effecting movement of the movablev jaw` toward the" fixed jaw to cause the jaws to-close andl seize stock inserted therebetween andfor thereafter moving' said closed jaws-ina direction to exert a yielding tensioning pull on thestockg, spring means movable with the gripper for yieldingly urg- Stir member in either t of 'thebottom y lasted; successively,

stock.` inserted therebetween.r and. for thereafter moving. saidvclosedr. jaws n ar` direction toexert a yielding tension;- ing.' pull on the stock;` adjustable spring. means movablev with the gripper for yieldingly urging the movable.: jawtoward` the fixed jaw, and meansk associated withf the power-operatedmeans forI positively moving the: mov-` able jaw away from the fixed jaw,l against` the.l resistance.`

of said spring means, to open the jaws-'and release the;`

stock and for thereafter positively returning. the openedz` jaws to their" original positions.

7. InV a lasting machine, an intermittently operating, gripper for' seizing and tensioning the stock.' to. be' lasted successively, in different locations along the` marginal edge of the bottom of ashoe, said gripper comprising. a1 power-operated: means; for:

away'fromy the fixed jaw', againstl the resistance of said?` to their original positions;

8. In a lasting machine, anI intermittently operating gripper forseizing and tensioning the stock to be lastech, successively, in differentzlo'cationsf along the marginal edge ofa shoe, said' grippercomprising a fixed; jaw and? a movable jaw, power-'operated means forfyield-l ingly effecting movement ofthemovable jaw toward the: fixed jaw to: causethe1jaws to` close andE seize stoclr'- in serted therebetweenand for: thereafter moving*saidfclosed jaws inv a directiont to exert. a; yielding tensioningpull onf the stock, spring means` operable independently of the.` power-operated means for holding: the jaws closed'V during4 movement' of thev gripper: to apply its` tensioningV pull, and means associated; with. the power-operated means for" positively movingv the movable jaw: away from; the fixedl` jaw, againstithe'resistance'of said spring means, tor openthe.y jaws and; release. the stock and for thereafter'- positively returning the; opened jaws to their'A original positions:

9'. a lasting` machine', an intermittently operating. gripper* fon seizingA and tensioning the stock to beslasted, successively, in; different locations'v along the marginal edge of the' bottom' of? a shoe, said gripper comprising a fixed iaw' and a movable jaw, power-operated meansfor yieldingly effecting movement of the movable jaw" y able independently of the power-operatedmeansy for holding the jaws closed dii-ringL movement of the gripper to apply its tensicyning` pull. and meansV associated with the power-operated mea-ns for positively moving the` movable iaw away' fronr the fixed jaw,` against the resistance of said' spring means. to open the jaws*Y and release the stock and for: thereafter positively returning` the opened ,jaws toy their original positions.

1'0.. In alasting machine; anl intermittently operating gripperV for seizing and' tensioning the stock toI be in different locations along: the marginal edgel of they bottomy of ay shoe, said gripper* comprising` a'v member mounted for reciprocating movement in' directions extending heightwise of the shoe being: lasted, friction means for resisting' movement of said direction; a fixed jaw secured? tosaid.

and.` for thereafter positively' returning,

operatings,

member and a movable jaw supported onthe member for movement toward and away from the fixed jaw, power-operated means for yieldingly effecting movement of said movable jaw toward the xed jaw to cause the jaws to close and seize stock inserted therebetween and for thereafter moving said member and said closed jaws, against the resistance of said friction means, in a direction to exert a yielding tensioning pull on the stock, additional means for yieldingly urging said movable jaw toward the fixed jaw, and means associated with the power-operated means for positively moving the movable jaw away from the fixed jaw, against the resistance of said additional means, to open the jaws and release the stock and for thereafter positively returning said member and the opened jaws to their original positions, against the resistance of the friction means.

11. In a lasting machine, an intermittently operating .gripper for seizing and tensioning the stock to be lasted,

successively, in different locations along the marginal edge of the bottom of a shoe, said gripper comprising a member mounted for reciprocating movement in directions extending heightwise of the shoe being lasted, friction means for resisting movement of said member in either direction, a fixed jaw secured to said member and a movable jaw supported on the member for movement toward and away from the fixed jaw, power-operated means for yieldingly effecting movement of said movable jaw toward the fixed jaw to cause the jaws to close and seize stock inserted therebetween and for thereafter moving said member and said closed. jaws, against the resistance of said friction means, in a direction to exert a yielding tensioning pull on the stock, spring means for yieldingly urging said movable jaw toward the fixed jaw, and means associated with the power-operated means for positively moving the movable jaw away from the fixed jaw, against the resistance of said spring means, to open the jaws and release the stock and for thereafter positively returning said member and the opened jaws to their original positions, against the resistance of the friction means.

12. In a lasting machine, an intermittently operating gripper for seizing and tensioning the stock to be lasted, successively, in different locations along the marginal edge of the bottom of a shoe, said gripper comprising a member mountedy for reciprocating movement in directions extending heightwise of the shoe being lasted, friction means in either direction, a Vfixed jaw secured to said member and a movable jaw supported on the member for movement toward and away from the fixed jaw, poweroperated means for yieldingly effecting movement of said movable jaw toward the fixed -jaw to cause the jaws to close and seize stock inserted therebetween and for thereafter moving said member and said closed jaws, against the resistance of said friction means, in a direction to exert a yielding tensioning pull on the stock, adiustable spring means for yieldingly urging said movable jaw toward the fixed jaw, and means associated with the power-operated means for positively moving the movable jaw away from the fixed jaw, against the resistance of said spring means, to open the iaws and release the stock and for thereafter positively returning said member and the opened jaws to their original positions, against the resistance of the friction means.

13. In a lasting machine, an intermittently operating gripper for seizing and tensioning the stock to be lasted, successively, in different locations along the marginal edge of the bottom of a shoe, said gripper comprising a member mounted for reciprocating movement in directions extending heightwise of the shoe being lasted, friction means for resisting movement of said member in either direction, a movable jaw pivotally supported on the member for movement toward and away from the fixed jaw, poweroperated means for yieldingly effecting movement of said movable jaw toward the fixed jaw to cause the jaws to close and seize stock inserted therebetween and for thereafter moving said member and said closed jaws, against the resistance of said friction means, in a direction to exert a yielding tensioning pull on the stock, additional means for yieldingly urging said movable jaw toward the fixed jaw, and means associated with the power-operated means for positively moving the movable jaw away from the fixed jaw, against the resistance of said additional for resisting movement of said member a fixed jaw secured to said member and means, to open the jaws and release the stock and for thereafter positively returning said member and the opened jaws to their original positions, against the resistance of the friction means.

14. In a lasting machine, an intermittently operating gripper for seizing and tensioning the stock to be lasted. successively, in different locations along the marginal edge of the bottom of a shoe, said gripper comprising a member mounted for reciprocating movement in directions extending heightwise of the shoe being lasted, friction means for resisting movement of said member in either direction, a fixed jaw secured to said member and a movable jaw pivotally supported on the member for movement toward and away from the fixed jaw, poweroperated means for yieldingly effecting movement of said movable jaw toward the fixed jaw to cause the jaws to close and seize stock inserted therebetween and for thereafter moving said member and said closed jaws, against the resistance of said friction means, in a direction to exert a yielding tensioning pull on the stock, spring means for yieldingly urging said movable jaw toward the fixed jaw, and means associated with the power-operated means for positively moving the movable fixed jaw, against the resistance of said spring means, to open the jaws and release the stock and for thereafter positively returning said member and the opened jaws to their original positions, against the resistance of the friction means.

15. In a lasting machine, an intermittently operating gripper for seizing and tensioning the stock to be lasted, successively, in different locations along the marginal edge of the bottom of a shoe, said gripper comprising a member mounted for reciprocating movement in directions extending heightwise of the shoe being lasted, friction means for resisting movement-of said member in either direction, a fixed jaw secured to said member and a movable jaw pivotally supported on the member for movement toward and away from the fixed jaw, power-operated means for yieldingly effecting movement of said movable jaw toward the fixed jaw to cause the jaws to close and seize stock inserted therebetween and for thereafter moving said member and said closed jaws, against the resistance of said friction means, in a direction to exert a yielding tensioning pull on the stock, adjustable spring means for yieldingly urging said movable jaw toward the fixed jaw, and means associated with the power-operated means for positively moving the movable jaw away from the fixed jaw, against the resistance of said spring means, to open the jaws and release the stock and for thereafter positively returning said member and the opened jaws to their original positions, against the resistance of the friction means.

16. In a lasting machine, an intermittently operating gripper for seizing and tensioning the stock to be lasted, successively, in different locations along the marginal edge of the bottom of a shoe, said gripper comprising a shaft mounted for reciprocating movement in directions extending heightwise of the shoe being lasted, friction means for resisting movement of the shaft in either direction, a fixed jaw secured to the shaft, a movable jaw pivotally supported on the shaft for movement toward and away from the fixed jaw, and an operating link connected to said movable jaw, power-operated means for yieldingly effecting movement of the link in a direction to effect movement of said movable jaw toward the fixed jaw to cause the jaws to close and seize stock inserted therebetween and for thereafter moving the shaft and the closed jaws, against the resistance of said friction means, in a direction to exert a tensioning pull on the stock, additional means for yieldingly urging the movable jaw toward the fixed jaw, connections between the link and the power-operated means for positively effecting movement of the link in the opposite direction to move the movable jaw away from the fixed jaw, against the resistance of said additional means, to open the jaws and releasethe stock, and connections between the shaft and the power-operated means for thereafter returning the shaft and the opened jaws to their original positions, against the resistance of the friction means.

17. In a lasting machine, an intermittently operating gripper for seizing and tensioning the stock to be lasted, successively, in different locations along the marginal edge of the bottom of a shoe, said gripper comprising a shaft mounted for reciprocating movement in directions extending heightwise of the shoe being lasted, friction jaw away from the an operating link connected to said movable jaw, power-operated means for yieldingly effecting movement of the link in a direction to effect movement of said movable jaw toward the fixed jaw to cause the jaws to close and seize stock inserted therebetween and for thereafter moving the shaft and the closed jaws, against the resistance of said friction means, in a direction to exert a tensioning pull on the stock, spring means for yieldingly urging the movable jaw toward the fixed jaw, connections between the link and the power-operated means for positively effecting movement of the link in the opposite direction to move the movable jaw away from the fixed jaw, against the resistance of said spring means, to open the jaws and release the stock, and connections between the shaft and the power-operated means for thereafter returning the shaft and the opened jaws to their original positions, against the resistance of the friction means.

1S. In a lasting machine, an intermittently operating gripper. for seizing and tensioning the stock to be lasted,

extending heightwise of the shoe being lasted, friction means for resisting movement of the shaft in either direction, a fixed jaw secured to the shaft, a movable jaw pivotally supported on the shaft for movement toward and away from the fixed jaw, and an operating link connected to said movable jaw, power-operated means for yieldingly effecting movement of the link in a direction to effect movement of said movable jaw toward the fixed jaw to cause the jaws to close and seize stock inserted therebetween and for thereafter moving the shaft and the closed jaws, against the resistance of said friction means, in a direction to exert a tensioning pull on the stock, adjustable spring means for yieldingly urging the movable jaw toward the fixed jaw, connections between the link and friction means for resisting movement of the shaft in either direction, a xed jaw secured to the shaft, a movable jaw pivotally supported on the shaft for movement toward and away from the fixed jaw and an operating link connected to the movable jaw, power-operated means for yieldingly effecting movement of the link 1n a dithe fixed jaw, connections between the link and the poweroperated means for positively effecting movement of the link in the opposite uirection to move the movable jaw away from the fixed jaw, against the resistance of said additional means, to open the jaws and release the stock, and connections between the shaft and the power-operated means for thereafter returning the shaft and the opened jaws to their original positions, against the resistance of the friction means.

20. In a lasting machine, an intermittently operating gripper for seizing and tensioning the stock to be lasted, successively, in different locations along the marginal edge of the bottom of a shoe, said gripper comprising a hollow shaft mounted for reciprocating movement in directions extending heightwise of the shoe being lasted, friction means for resisting movement of the shaft in either direction, a fixed jaw secured to the shaft, a movable jaw pivotally supported on the shaft for movement toward and away from the fixed jaw and an operating link connected to the movable jaw, power-operatedjmeans for yieldingly effecting movement of the link in a direction to effect movement of said movable jaw toward the fixed jaw to cause the jaws to close and seize stock inserted therebetween and for thereafter moving the shaft and the closed jaws, against the resistance of the friction means, in a direction to exert a tensioning pull on the stock, spring means within the hollow shaft for yieldingly urging the movable jaw toward the fixed jaw, connections between the link and the power-operated means for positively effecting movement of the link in the opposite di- .rection to move the from the xed the shaft and the power-operated means for thereafter returning the shaft and the opened jaws to their original positions, against the resistance of the friction means.

21. In a lasting machine, an intermittently operating gripper for seizing and tensioning the stock to be lasted, successively, in different locations along the marginal edge of the bottom of a shoe, said gripper comprising a hollow shaft mounted for reciprocating movement in directions extending heightwse of the shoe being laste'd` toward and away from the fixed jaw and an operating link connected to the movable jaw, power-operated means for yieldingly effecting movement of the link in a direction to effect movement of said movable jaw toward the fixed jaw to cause the jaws to close and seize stock inserted therebetween and for thereafter moving the shaft and the closed jaws, against the resistance of the friction means, in a direction to exert a tensioning pull on the stock, adjustable spring means within the hollow shaft for yieldingly urging the movable jaw toward the fixed jaw, connections between the link and the power-operated means for positively effecting movement of the link in the opposite direction to move the movable jaw away from the fixed jaw, against the resistance of said spring means, to open the jaws and release the stock, and connections between the shaft and the power-operated means for thereafter returning the shaft and the opened jaws to their original positions, against the resistance of the friction means.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,432,165 Lawson Dec. 9, 1947 2,470,170 Hubbard May 17, 1949 

